exynos5800-peach-pi: suspend/resume (still) broken

[Abhilash Kesavan]

Hi,

On Fri, Mar 20, 2015 at 9:59 PM, Abhilash Kesavan
<kesavan.abhilash at gmail.com> wrote:
> Hi Javier,
>
> On Fri, Mar 20, 2015 at 9:46 PM, Javier Martinez Canillas
> <javier.martinez at collabora.co.uk> wrote:
>> Hello Abhilash,
>>
>> On 03/20/2015 03:23 PM, Abhilash Kesavan wrote:
>>>> On 03/17/2015 06:35 PM, Kevin Hilman wrote:
>>>>>
>>>>> Anyone else having better luck with suspend/resume on peach-pi?
>>>>>
>>>>
>>>> # echo +2 > /sys/class/rtc/rtc0/wakealarm && echo mem > /sys/power/state
>>>>
>>>> Suspend and CPUs shutdown seems to succeed according to [0] but the system
>>>> never wakes up...
>>>>
>>>> I also tried to wakeup the system with the keyboard and the trackpad that is
>>>> a wake up source but it does not work either.
>>>>
>>>> I remember that when the 5420 s2r support series were posted, aclk200_disp1
>>>> and aclk300_disp1 clocks needed to be marked as CLK_IGNORE_UNUSED but afaiu
>>>> that was only because display support was not yet merged but it is now.
>>>>
>>>> I tried anyways both marking those clocks as CLK_IGNORE_UNUSED and passing
>>>> the clk_ignore_unused to the kernel command line but did not work either.
>>>>
>>>> Abhilash, Vikas, Pankaj,
>>>>
>>>> Any ideas of what could be causing this regression? It seems that by the
>>>> time the Exynos5420 S2R support landed in mainline, it was already not
>>>> working which makes it hard to bisect what caused the issue.
>>>
>>> I remember the Pi power LED changing color from blue on suspend. Does
>>
>> Thanks a lot for answering. Who manages that LED? is the kernel or the
>> firwmare in the EC? I tried suspend to ram using ChromeOS 3.8 kernel and
>> I see that the blue LED is indeed turned off on suspend but that does not
>> happen in mainline.
>
> I am not too sure. It was just something I remembered from earlier.
>
>>
>>> that happen ? I'll try reproducing the issue and then probably use an
>>> old working s2r branch in one of my local repos to track this down.
>>>
>>
>> If I checkout mainline with HEAD in your commit adc548d77c22
>> ("ARM: EXYNOS: Use MCPM call-backs to support S2R on exynos5420") + the
>> patch you mentioned back then to keep the aclk200_disp1 and aclk300_disp1
>> clocks enabled even when not used [0], I have S2R working. But even with
>> that commit, I don't see the blue LED to be turn off like is the case in
>> the ChromeOS 3.8 kernel.
>>
>> So I think you can use that as a base. I tried bisecting but it is tricky
>> due other issues masking the S2R regression. I also tried to compare the
>> diff between adc548d77c22 and v3.19-rc1 that is the first known bad afaict
>> but didn't find any relevant either.
>>
>> By adding printouts I can tell that all the CPUs enter exynos_power_down()
>> in arch/arm/mach-exynos/mcpm-exynos.c and also the last man disables the
>> cluster for both Cortex A-15 and A-7 clusters.
>>
>> So it seems that the problem is on the resume path.
>
> I have made some progress on this. This is the current state:
>
> If I use next-20141114 (which was when the S2R code first appeared in
> linux-next), then all is good. next-20141117 is fine too but things
> are broken in next-20141118.
> I have narrowed it down to the commit: "ae43b32 ARM: 8202/1:
> dmaengine: pl330: Add runtime Power Management support v12". The only
> way I see this impacting s2r is because it disables the dma pclk while
> suspending or before.
>
> Checking further, will update in a bit.

OK, so disabling the mdma0 node in "arch/arm/boot/dts/exynos5420.dtsi"
gets things working. Like Kevin mentioned in the initial report, I
need to disable DRM else there is a crash while suspending. With these
two changes, on linus' tree and kgene's for-next s2r works fine.

On linux-next, I need to disable CONFIG_MWIFIEX too.

Also, I observe cros-ec-spi transfer failures during resume and
sometimes it is unable to re-enable the tps fets causing a crash.
However, that would be a driver specific issue.

Regarding the mdma0 disablement, it looks like for the system to
suspend properly the mdma0 pclk needs to stay on.

Regards,
Abhilash
>>
>>> Regards,
>>> Abhilash
>>>>
>>
>> Best regards,
>> Javier
>>
>> [0]:
>> diff --git a/drivers/clk/samsung/clk-exynos5420.c b/drivers/clk/samsung/clk-exynos5420.c
>> index 848d602efc06..d8b66339d564 100644
>> --- a/drivers/clk/samsung/clk-exynos5420.c
>> +++ b/drivers/clk/samsung/clk-exynos5420.c
>> @@ -932,14 +932,14 @@ static struct samsung_gate_clock exynos5x_gate_clks[] __initdata = {
>>         GATE(0, "aclk400_mscl", "mout_user_aclk400_mscl",
>>                         GATE_BUS_TOP, 17, 0, 0),
>>         GATE(0, "aclk200_disp1", "mout_user_aclk200_disp1",
>> -                       GATE_BUS_TOP, 18, 0, 0),
>> +                       GATE_BUS_TOP, 18, CLK_IGNORE_UNUSED, 0),
>>         GATE(CLK_SCLK_MPHY_IXTAL24, "sclk_mphy_ixtal24", "mphy_refclk_ixtal24",
>>                         GATE_BUS_TOP, 28, 0, 0),
>>         GATE(CLK_SCLK_HSIC_12M, "sclk_hsic_12m", "ff_hsic_12m",
>>                         GATE_BUS_TOP, 29, 0, 0),
>>
>>         GATE(0, "aclk300_disp1", "mout_user_aclk300_disp1",
>> -                       SRC_MASK_TOP2, 24, 0, 0),
>> +                       SRC_MASK_TOP2, 24, CLK_IGNORE_UNUSED, 0),
>>
>>         GATE(CLK_MAU_EPLL, "mau_epll", "mout_mau_epll_clk",
>>                         SRC_MASK_TOP7, 20, 0, 0),
>>